renamed bmp structs to not conflict with windows.h
renamed bmp structs to not conflict with windows.h
minor cleanups
separate file checks for each filetype
added get_extension
removed quad and integer_stretch (unused)
removed quad and integer_stretch (unused)
removed quad, cleanups
moved static functions into anonymous namespace
tweaked color palette
tweaked default palette
sped up colorize
adding .travis.yml, commenting some self-assignments